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Exam 3 Review Slides
Lectures 9-12Chapters 5, 6, and 7
Types/Functions of Epithelial Tissue
• Types of epithelium• Covering and Lining Epithelium
– External Surfaces, e.g., skin, Internal surfaces
• Glandular Epithelium
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• Functions of Epithelial Tissue– Physical protection– Control of permeability
• Secretion, Absorption, Filtration
– Provide sensation– Provide specialized secretions (glands)
Characteristics of Epithelial Tissue
• Specialized contacts with other cells
• Polarity (different ends of cell do different things)
• Avascularity (no blood supply)
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• Regeneration (can divide to make new cells)
• Cellularity (lots of cells in close contact)
Remember: Epithelial tissues always have a free surface and a basement membrane
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Basal Lamina
Two components:
Lamina Lucida- glycoproteins and fine protein filaments
B i f f b t f
Formerly called: Basement membrane
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- Barrier for passage of substances from underlying tissue into epithelium
Lamina Densa- bundles of coarse protein fibers- gives basal lamina its strength
Figure from: Martini, Fundamentals of Anatomy & Physiology, Benjamin Cummings, 2004
Lamina = thin layer
Classification of Epithelial Tissues
• Shape– Squamous (Thin, flat, irregular in shape)– Cuboidal (Square or cuboidal)
Epithelial tissues are classified according to both their:
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( q )– Columnar (Rectangular, tall)
• Type of layering (stratification)– Simple (one layer)– Stratified (two or more layers)– Note that classification of stratified
epithelium is based on the shape of the superficial, not deep, layers
Characteristics of Epithelial TissueSpecialized Contacts
Tight junction – forces substances to go through cells, rather than being able to pass between them
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Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Gap junction – allow rapid passage of small molecules/ions between cells
Desmosome – binds cells together firmly so they stay connected
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Review
NAME OF ET DESCRIPTION STRUCTURE
LOCATION FUNCTION
SIMPLESQUAMOUS
a single layer of flattened cells
linings of air sacs, capillaries, lymph vessels, body cavities; covering ventral organs
diffusion, reduction of friction
SIMPLE CUBOIDAL
a single layer of cube-shaped cells with
linings of kidney tubules, ducts of
absorption,secretion
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CUBOIDAL shaped cells with large centrally located nuclei
tubules, ducts of glands
secretion
SIMPLE COLUMNAR
a single layer of tall cells with basally located nuclei, goblet cells, & mucrovilli
lining of intestine protection,absorption,secretion
PSEUDO-STRATIFIEDCOLUMNAR
a single layer of tall cells with scattered nuclei, cilia, & goblet cells
lining of trachea,lining of fallopian tube
protection, secretion
Review
NAME OF ET DESCRIPTION STRUCTURE
LOCATION FUNCTION
STRATIFIEDSQUAMOUS
many layers of flattened cells
keratinized = epidermis;non-keratinized = lining of vagina, anus, throat, mouth
protection
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TRANSITIONAL several layers of cells that change shape under pressure
lining of urinary bladder and ureters
Distensibility (able to stretch)
GLANDULAR simple cuboidal lining the ducts of glands
secretion
Review of Epithelial Tissues
• Exocrine glands have several different mechanisms of secretion
• Glands are specialized epithelium
– Secrete on to a surface (exocrine)
– Secrete into a duct (exocrine)
– Secrete into the blood (endocrine)
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– Merocrine
• Release of product from vesicles by exocytosis
– Apocrine
• Loss of cytoplasm containing secretion; Apical portion of cytoplasm is shed
– Holocrine
• Entire cell is packed with secretion and then bursts
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Membranes
Serous• line body cavities that l k i t t id
Mucous• line tubes and organs th t t t id ld
A membrane is a combination of epithelium and connective tissue that covers and protects other structures and tissues. Technically, then, a membrane is an organ.
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lack openings to outside• reduce friction• inner lining of thorax and abdomen• cover organs of thorax and abdomen• secrete serous fluid
that open to outside world• lining of mouth, nose, throat, digestive tract, etc.• secrete mucus
Cutaneous• covers body• skin
Synovial• surround joint cavities
ReviewNAME OF CT DESCRIPTION LOCATION FUNCTION
MESENCHYME Embryo gives rise to all other CT’s
AREOLAR gel-like matrix with fibroblasts, collagen and elastic fibers
beneath ET (serous membranes around organs & lining cavities)
diffusion, cushioning organs
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ADIPOSE closely packed adipocytes with nuclei pushed to one side by fats
beneath skin, breasts, around kidneys & eyeballs
insulation, energy store, protection
RETICULAR network of reticular fibers in loose matrix
basement membranes,lymphatic organs
support
DENSEREGULAR
dense matrix of collagen fibers
tendons, ligaments attachment (high tensile strength)
DENSEIRREGULAR
loose matrix of collagen fibers
dermis of skin strength in several directions
ReviewNAME OF CT DESCRIPTION LOCATION FUNCTION
ELASTIC CT matrix of elastic fibers
lung tissue, wall of aorta
durability with stretch
HYALINECARTILAGE
chondrocytes in lacunae in amorphous matrix
embryonic. skeleton, costal cart, tip of nose, trachea, larynx
support
FIBRO- less firm than above intervertebral discs, tensile strength,
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CARTILAGE pubic symphysis shock absorber
ELASTICCARTILAGE
above plus elastic fibers
external ear, epiglottis
shape maintenance plus flexibility
BONE concentric circles of calcified matrix
Bones support, protection, movement, Ca ++
storage, hematopoiesis
BLOOD red cells, white cells and platelets in liquid plasma
in heart and blood vessels
transport of nutrients, wastes & gases
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Name of CT
Different types of this CT
Main types of cells present
Main types of fibers present
Consistency of matrix Examples of Locations
CT Proper1) Areolar (Loose)2) Dense regular3) Dense irregular4) Adipose5) Reticular6) Elastic
1) Fibroblasts2) Fibroblasts3) Fibroblasts4) Adipocytes5) Fibroblasts6) Fibroblasts
1) Collagen, Elastic2) Collagen3) Collagen4) Reticular5) Reticular6) Elastic
Semi-liquid1) Skin, between muscles2) Tendons, ligaments3) Dermis 4) Body fat areas5) Stroma of liver, spleen6) Lungs, airways, arteries/heart
Cartilage 1) Hyaline 1) Collagen (sparse) Semi solid 1) Ribs ends of bones
Connective Tissue (CT) Summary Table
Three main components of ALL CT: cell, fibers, ground substance
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Cartilage 1) Hyaline2) Fibrocartilage3) Elastic
(All) Chondrocytes1) Collagen (sparse)2) Collagen (dense)3) Elastic
Semi-solid, gelatinous
1) Ribs, ends of bones2) Intervertebral disks3) Pinna of ear, epiglottis
Bone 1) Dense2) Spongy
(All) Osteocytes Collagen Solid (hydroxyapatite)
1) Outer portions of bone2) Inner portions of bone
Blood--
1) RBCs2) WBCs3) Platelets (cell fragments)
Fibrinogen (soluble) Liquid Blood vessels, heart
Lymph -- Lymphocytes Reticular (in stroma of lymphoid organs)
Liquid Lymph vessels
-cyte = fully differentiated; -blast = young, actively synthesizing cell
Connective Tissue - Major Cell Types
Fibroblasts• fixed cell• most common cell; alwaysin CT proper • large, star-shaped• produce fibers
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produce fibers• produce ground substance
Macrophages• wandering cell• phagocytic• important in defense• derived from circulating monocytes
Connective Tissue FibersCollagenous fibers
• thick• composed of collagen• great tensile strength• hold structures together• abundant in dense CT• tendons, ligaments
Elastic fibers• bundles of microfibrils embedded in elastin• fibers branch• elasticity• vocal cords, air
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tendons, ligaments vocal cords, air passages
Reticular fibers• very thin collagenous fibers• highly branched• form supportive networks
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The “Ground Substance” of CT
glucosamine
16Figures from: Alberts et al., Essential Cell Biology, Garland Press, 1998
VERY hydrophilic!
Very active in controlling passage of substances through this portion of the matrix and keeping CT hydratedGAGs = glycosaminoglycans (negatively charged
polysaccharides); a major molecule in ground substance
Tendons and Ligaments
Tendons: Connect muscle to boneLigaments: Connect bone to boneAponeuroses: Broad, fibrous sheets; usually attach muscle to muscle (or bone)
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CT Framework of the Body
18Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Fascia connects the organs of the dorsal and ventral cavities with the rest of the body
Provide:- Strength- Stability- Organ position- Conduits
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Muscle – Overview
• General characteristics– Elongated cells with special properties
– Muscle cells (myocytes) = muscle fibers
– Contractile (major property of all muscle)
U ti (thi ) d i (thi k) f t ti
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– Use actin (thin) and myosin (thick) for contraction
• Three types of muscle tissue– Cardiac (involuntary)
– Skeletal
– Smooth
Review of Muscle TypesNAME OFMUSCLETISSUE
DESCRIPTION OFSTRUCTURE
TYPE OFCONTROL
LOCATION FUNCTION
SKELETALMUSCLE
long, thin fibers with many nuclei and striations
Voluntary attached to bones to move bones
SMOOTHMUSCLE
spindle shaped cells with one centrally l t d l
Involuntary walls of visceral hollow organs, i i f
to move substances through
(i
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located nucleus, lacking striations
irises of eyes, walls of blood vessels
passageways (i.e. food, urine, semen),
constrict blood vessels, etc
CARDIAC MUSCLE
a network of striated cells with one centrally located nucleus attached by intercalated discs
- Intercalated disks consist of gap junctions and desmosomes
Involuntary heart pump blood to lungs and body
Nervous Tissue• found in brain, spinal cord, and peripheral nerves• conduction of nerve impulses• basic cells are neurons• sensory reception• neuroglial cells are supporting cells
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Introduction to Inflammation
22Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Restoration of homeostasis after tissue injury or infections involves two processes: 1) inflammation and 2) repair.
Hallmarks of inflammation: Redness, heat, pain, swelling, and loss of function
(Inflammation = ‘-itis’)
Functions of the Integumentary System
• Functions of the integument– Protection (from mechanical/chemical/bacterial
damage, UV radiation)– Temperature regulation (extreme heat, extreme
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cold) and Fluid conservation– Excretion– Vitamin D production– Sensation (touch, pressure)
Layers of the Epidermis - Overview
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Thick and Thin Skin
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Thin (0.07-0.12 mm)(epidermal thickness) Thick (0.8-1.4 mm)
(epidermal thickness)
Thick skin - palms of hands, soles of feet; five epidermal layers
Thin skin - everywhere else; four epidermal layers (no s. lucidum)
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Cells of the Epidermis
• Epidermis of the skin is classified as a keratinized stratified squamous epithelium
• Cells of the epidermis include– Keratinocytes (90%)
• Keratin – a tough, fibrous intracellular protein (protection)• Lamellar granules (waterproofing, extracellular)
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Lamellar granules (waterproofing, extracellular)
– Melanocytes (8%)• Produce melanin (protection from UV radiation)
– Langerhans cells (1-2%)• Migrate to skin from bone marrow• Participate in skin’s immune response (dendritic cells)
– Merkel cells (< 1%)• Least numerous; specialized epithelial cells• Function in sensation of touch
Skin Color
Genetic Factors• varying amounts and type of melanin• varying size/number of melanin granules• albinos lack melanin (but not melanocytes!)
Physiological Factors• dilation of dermal blood vessels (erythema)
• constriction of dermal blood vessels (less pink, pale = pallor)
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(but not melanocytes!)
Environmental Factors• sunlight• UV light from sunlamps • X rays
• level of oxygenation of blood* normal = pink (fair-skinned) * low = bluish (cyanosis)
• carotene -> Vit A (yellow)
• jaundice (yellow)
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Skin Color and Melanin
Dark-skinned Fair-skinned
28Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004
Melanocytes produce melanin
- tyrosine melanin- UV radiation up-regulates production of melanin- Caucasian vs. dark-skinned
* number vs. activity* layer of epidermis
Keratin and Vitamin D
• Keratin– Protection
– Water resistance
• Vitamin D3 (“sunshine vitamin”)
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– After UV irradiation epidermal cells in s. spinosum and s. basale convert a cholesterol-related steroid to Vit D3
(cholecalciferol)
– Vit D3 – absorption of calcium and phosphorus by small intestine
DermisPapillary layer- areolar connective tissue (CT)- capillaries and sensory neurons- dermal papillae- fingerprints (with epi. ridges)
Reticular layer- dense, irregular CT
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, g- collagen fiber bundles extend upward and downward- also contains elastic fibers and cells of CT proper- accessory organs of integumentary system (from epi.)- cleavage or tension lines- flexure lines
Figure adapted from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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Subcutaneous Layer
Basal lamina
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- Stabilization of dermis
- Areolar and adipose tissue
- Effect of hormones- Reservoir of blood
Also called ‘hypodermis’. This is the superficial fascia.
- INSULATION
Hair (pilo-)
• epidermal cells
• tube-like depression
• extends into dermis
• hair root (in dermis)
• hair shaft (outer 1/3)
Basal lamina
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• hair shaft (outer 1/3)
• hair papilla
• dead epidermal cells
• melanin• arrector pili muscle
A hair in the scalp grows for 2-5 years, about 0.33mm/day
Nerves in root hair plexus
(from epidermis)
Hair Follicles
Types of hair:
1. Lanugo – long, blond, fine (fetal, anorexia nervosa)
Hair color
33Figure adapted from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Some hair color
2. Vellus – short, blond (children)
3. Terminal – course, pigmented (adults)
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Sebaceous (Oil) Glands
• holocrine glands
• usually associated with hair follicles
• secrete sebum, a waxy, oily
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• absent on palms and soles
material
• inhibits growth of bacteria
• lubricates and protects keratinof hair shaft, and conditions skin Sebaceous follicles – not
associated with hair. Discharge directly on to skin. On face, back, chest, nipples and male sex organs.
Sweat Glands
• apocrine (merocrine secr.)glands- associated with hair follicles- thick, odorous secretion
• also called sudoriferous glands
• eccrine (merocrine secr.) glands
Sweating with wetness = diaphoresis
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• ceruminous glands
• mammary glands
- most numerous- palms, soles, forehead, neck,back
- directly on to surface- watery secretion- for thermoregulation
Specialized (apocrine secretion)
Nails
(Perionychium)
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Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007
Know these termsHyponychium
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Regulation of Body TemperatureHyperthermia – Abnormally highbody temperature
May be caused by- environment (heat, humidity)- illness (fever [>=37.20C], pyrexia)- anesthesia (malignant h.)
Corrected by loss of heat by
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Corrected by loss of heat by radiation, convection, conduction, evaporation
Heat exhaustion (prostration)- Fatigue- Dizziness- Headache- Muscle cramps- Nausea- May lead to heat stroke
Regulation of Body TemperatureHypothermia – Abnormally low body temperature (at least 20C below normal body temp)
May be caused by:
- exposure to cold (primary)
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exposure to cold (primary)
- illness (secondary)
- surgical induction (clinical)
Cardiac arrest is likely if temperature falls below 28oC (82oF)
Corrected by mechanisms to retain body heat (see left)
Healing of Cuts
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Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Tissue repair can occur by either: 1) regeneration – healing with tissue that was originally present2) fibrosis – healing with ‘scar’ tissue (carried out by fibroblasts)
1. Bleeding/clotting
2. Scab formation
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Healing of Cuts
40Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
3. Epidermal cell migration and collagen production
4. Shedding of scab; covering of wound with epithelium